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Erosion Control of Steep Open Channels Using Articulated Concrete Blocks.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Erosion Control of Steep Open Channels Using Articulated Concrete Blocks./
作者:	Marandi, Mohammad Omid.
面頁冊數:	1 online resource (106 pages)
附註:	Source: Masters Abstracts International, Volume: 84-02.
Contained By:	Masters Abstracts International84-02.
標題:	Shear tests. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29239090click for full text (PQDT)
ISBN:	9798841575344

Erosion Control of Steep Open Channels Using Articulated Concrete Blocks.
Marandi, Mohammad Omid.

Erosion Control of Steep Open Channels Using Articulated Concrete Blocks. - 1 online resource (106 pages)

Source: Masters Abstracts International, Volume: 84-02.

Thesis (M.Eng.Sc.)--The University of Western Ontario (Canada), 2022.

Includes bibliographical references

Overtopping flow can undermine the stability of hydraulic structures including embankments and spillways through the shear stress and the subsequent soil erosion. Increased flow velocity can cause scour, which can result in the failure of dams, bridges, and overall open channel hydraulic structures. Sediment transport is another crucial issue in open channels that can cause severe socioeconomic and environmental consequences. Two general approaches are commonly considered for scour prevention. The first approach involves flow modifications to minimize the corresponding effects on the structures. The second approach is associated with bed armoring and placing physical barriers on the natural bedding such as the Articulated Concrete Block system (ACBs). The Articulated Concrete Block (ACB) system includes a series of concrete blocks or slabs that are interconnected using steel or synthetic cables, which are commonly employed for the bed and bank protection of open channels. Two flow-induced failure mechanisms can undermine the performance of ACBs: Direct failure, which is attributed to the direct impact of free-surface flow on concrete blocks leading to the overturning or rolling-up of the edge of the ACB. Indirect failure is associated with the scouring of the underlying bedding that can result in the deformation of the ACB structure and its failure. The main objective of this study is to analyze the ACBs protection layer, understand the factors that can influence scouring, and develop measures to reduce the failure risks and minimize the amount of sediment transport of the bedding and the subgrade. The indirect failure mechanisms of ACBs laid over the downstream face of an embankment are explored through a suite of laboratory experiments (∼ 40 tests). The effects of substrate structure, soil particle size, the slope of the embankment, and different types of permeable filters (i.e., geotextile, geogrid, and filter cloth mats) on the incipient motion of the bedding and the amount of soil loss are assessed. The stability of the embankment is investigated through various configurations with different water depths and velocities. Results show that overtopping flow with high velocity causes soil erosion and sediment transport in a very short period of time with the absence of a protection layer. ACB can noticeably improve channel stability and reduce sediment transport due to its perfect contact with subgrade and its flexibility. However, the risk of ACB failure increases if the subgrade is not designed and implemented properly. ACBs are to be in close contact with the subgrade and the fabrics and spaces between the blocks should be optimized otherwise, the overtopping of the blocks and sediment transport happen. The fabrics placed in between the layers can prevent the suction of the finer particles and reduce the risk of failure. Coarser and well-grade particles underneath the ACB structure can drain more water due to their higher hydraulic conductivity and improve the stability of the embankment. Further, risks of failure are higher near the downstream toe, which can be partly controlled by sufficient flow drainage and anchoring the downstream segments. The subgrade beneath the ACB is to be uniformly compacted so that the water flow passes through the blocks and over the subgrade steadily. The median diameter and the slope of the embankment played a key role in mitigating the amount of soil loss.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798841575344Subjects--Topical Terms:

3681835
Shear tests.
Index Terms--Genre/Form:

542853
Electronic books.

Erosion Control of Steep Open Channels Using Articulated Concrete Blocks.
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245 1 0 $a Erosion Control of Steep Open Channels Using Articulated Concrete Blocks.
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300 $a 1 online resource (106 pages)
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500 $a Source: Masters Abstracts International, Volume: 84-02.
500 $a Advisor: Najafi, Mohammad Reza; Sadrekarimi, Abouzar.
502 $a Thesis (M.Eng.Sc.)--The University of Western Ontario (Canada), 2022.
504 $a Includes bibliographical references
520 $a Overtopping flow can undermine the stability of hydraulic structures including embankments and spillways through the shear stress and the subsequent soil erosion. Increased flow velocity can cause scour, which can result in the failure of dams, bridges, and overall open channel hydraulic structures. Sediment transport is another crucial issue in open channels that can cause severe socioeconomic and environmental consequences. Two general approaches are commonly considered for scour prevention. The first approach involves flow modifications to minimize the corresponding effects on the structures. The second approach is associated with bed armoring and placing physical barriers on the natural bedding such as the Articulated Concrete Block system (ACBs). The Articulated Concrete Block (ACB) system includes a series of concrete blocks or slabs that are interconnected using steel or synthetic cables, which are commonly employed for the bed and bank protection of open channels. Two flow-induced failure mechanisms can undermine the performance of ACBs: Direct failure, which is attributed to the direct impact of free-surface flow on concrete blocks leading to the overturning or rolling-up of the edge of the ACB. Indirect failure is associated with the scouring of the underlying bedding that can result in the deformation of the ACB structure and its failure. The main objective of this study is to analyze the ACBs protection layer, understand the factors that can influence scouring, and develop measures to reduce the failure risks and minimize the amount of sediment transport of the bedding and the subgrade. The indirect failure mechanisms of ACBs laid over the downstream face of an embankment are explored through a suite of laboratory experiments (∼ 40 tests). The effects of substrate structure, soil particle size, the slope of the embankment, and different types of permeable filters (i.e., geotextile, geogrid, and filter cloth mats) on the incipient motion of the bedding and the amount of soil loss are assessed. The stability of the embankment is investigated through various configurations with different water depths and velocities. Results show that overtopping flow with high velocity causes soil erosion and sediment transport in a very short period of time with the absence of a protection layer. ACB can noticeably improve channel stability and reduce sediment transport due to its perfect contact with subgrade and its flexibility. However, the risk of ACB failure increases if the subgrade is not designed and implemented properly. ACBs are to be in close contact with the subgrade and the fabrics and spaces between the blocks should be optimized otherwise, the overtopping of the blocks and sediment transport happen. The fabrics placed in between the layers can prevent the suction of the finer particles and reduce the risk of failure. Coarser and well-grade particles underneath the ACB structure can drain more water due to their higher hydraulic conductivity and improve the stability of the embankment. Further, risks of failure are higher near the downstream toe, which can be partly controlled by sufficient flow drainage and anchoring the downstream segments. The subgrade beneath the ACB is to be uniformly compacted so that the water flow passes through the blocks and over the subgrade steadily. The median diameter and the slope of the embankment played a key role in mitigating the amount of soil loss.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Shear tests. $3 3681835
650 4 $a Failure. $3 3561225
650 4 $a Flow velocity. $3 3564851
650 4 $a Creeks & streams. $3 3685269
650 4 $a Concrete. $3 666349
650 4 $a Soil erosion. $3 602940
650 4 $a Sediment transport. $3 555890
650 4 $a Grain size. $3 3682362
650 4 $a Performance evaluation. $3 3562292
650 4 $a Sedimentation & deposition. $3 3566241
650 4 $a Shear strength. $3 3680813
650 4 $a Hydraulics. $3 669758
650 4 $a Shear stress. $3 3681838
650 4 $a Aquatic sciences. $3 3174300
650 4 $a Fluid mechanics. $3 528155
650 4 $a Hydraulic engineering. $3 613609
650 4 $a Mechanics. $3 525881
650 4 $a Physics. $3 516296
650 4 $a Sedimentary geology. $3 3173828
650 4 $a Soil sciences. $3 2122699
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0792
690 $a 0204
690 $a 0218
690 $a 0346
690 $a 0605
690 $a 0594
690 $a 0481
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a The University of Western Ontario (Canada). $3 1017622
773 0 $t Masters Abstracts International $g 84-02.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29239090 $z click for full text (PQDT)